Spray 12 cup bundt pan with cooking spray and flour.
Cream the butter and sugar in mixer.
Add one egg at a time, scrape sides. Add vanilla.
In separate extra large bowl mix flour, soda, cinnamon, lavender, and salt together.
Alternately mix part flour, part sour cream into the batter.
Add Blackberry Preserves.
Pour into bundt pan. Bake for 15 minutes at 300 degrees and then increase heat to 350 degrees for an additional 40 to 45 minutes.
Let cool then remove from pan.
Once cake is completely cool heat remaining blackberry preserves in sauce pan.
Add powdered sugar until desired consistency. Drizzle on cake and then add fresh blackberries optional.
Notes
Bundt cake is great for making ahead. Once cool, wrap well in plastic wrap and then in foil or a large bag for freezing. Make the glaze once thawed, right before serving.Use an extra large bowl for the batter as there is a lot of batter and needs room for stirring.